Radio dying momentarily if revs drop when pulling away?

[Typ 5K]

Been noticing an odd thing with my '09 1.4 TSI (122) recently - if I don't give it enough beans when I pull away from traffic lights and the revs drop a bit (but not close to the point of stalling), occasionally (think mainly when the engine is cold), the radio (RCD210) will die for a second or two (ie. sound will fade, and backlight will go off if it is on). Think I've seen the instrument lighting doing the same thing on occasion too. Looks to me like the voltage to the radio and/or IP is dropping with the revs, which of course shouldn't be happening (unless someone has sneakily replaced my alternator with a dynamo!). Anybody come across this before?

[Typ 5K]

A belated follow-up: after some googling, I've found similar problems described on some German forums (see, for instance http://www.golfv.de/145080-zu-kleine-batterie-verbaut-garantie.html). It appears that this issue is known to VW and they have issued a TPI (TPI 2023286) stating that the factory-installed 44Ah battery is insufficient and should be replaced with a 72Ah one. Also, the alternator may need to be uprated.